# how come Photons are deemed to be mass less when the equation for its energy contains mass=E= Mass x C^2?

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Ummmmmmm ...

Where did you get the idea that equation says something with energy must also have mass?

• you missed the whole point about frequency meaning in Power = hf

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• Wrong equation. E = hv where

E= energy

h = Planck constant, which really is "constant"

v = frequency, NOT velocity.

The speed of light IS NOT "CONSTANT"!!!!!

• goring, your perfect square wave has an infinite acceleration unless the amplitude of your infinite frequency is zero.  So does a wave of infinite frequency with zero amplitude represent a real wave?  But what has that to do with the question?

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• E = mc^2 only applies to an object at rest. Photons are never at rest. The full equation is

E^2 = (mc^2)^2 + (pc)^2

The energy of a photon is also given by  E = hf where f is its frequency and h is planks constant.

• Energy is just a transfer function between Power and time= no time no energy

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• Anonymous
3 months ago

E= Mass x C^2 is only for stationary objects.

In general

E^2 = (Mass x C^2)2 + (Momentum x C)^2

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